Wiped thin film evaporation and treatment apparatus

ABSTRACT

A thin film treatment apparatus, especially for treatment of viscous materials, which is of the type comprising a rotationally symmetrical treatment chamber which is surrounded by a heatingor cooling jacket and which contains a rotor. The rotor is equipped with material conveying means which are inclined with respect to the axis of rotation of the rotor. Further, the rotor is provided with wiper means which extend generally axially and are arranged in offset fashion with respect to the conveying means in the peripheral or circumferential direction. According to an important aspect of the invention, the conveying means are formed of a plurality of vane stubs arranged in at least one axial row, wherein the confronting ends of neighboring vane stubs, viewed in the axial direction, are spaced from one another and, in each instance, form a gap. Further, the wiper means are offset in trailing fashion with respect to the row of vane stubs through an angle less than 90* in the direction of rotation of the rotor and at least partially bridge/or overlie the gap between neighboring vane stubs.

United States Patent 1151 3,695,327 Widmer [451 Oct. 3, 1972 [5 WIPEDTHIN FILM EVAPORATION FOREIGN PATENTS OR APPLICATIONS AND TREATMENTAPPARATUS. 1,061,026 4/1954 France 159/6 w [72] Inventor: Fritz Widmer,Fallanden, Switzerland Primary Examiner-Wilbur L. Bascomb, Jr. AssistantExaminer-J. Sofer [73] Asslgnee' Luwa AG Artorney--Werner W. Keeman [22]Filed: March 18, 1970 211 Appl. No.: 20,674 [57] ABSIRACT A thin filmtreatment apparatus, especially for treatment of viscous materials,which is of the type com- [30] Forelgn Apphcauon Priomy Data prising arotationally symmetrical treatment chamber March 21, 1969 Switzerland..428l/69 which is surrounded y a heatingor cooling jacket and whichcontains a rotor. The rotor is equipped with 52 us. c1. ..159/6 w,159/49 material conveying means which are inclined with 51 Int. Cl."B0111 1/22 respect o the ads of rotation of the rotor. Furth 58 Field6: Search ..159/6, 6 w, 49; 202/236; the rotor provlded Wlth wiper awhich extend 203/89 generally axially and are arranged in offset fashionI with respect to the conveying means in the peripheral 5 References aor circumferential direction. According to an important aspect of theinvention, the conveying means are UNITED STATES PATENTS formed of aplurality of vane stubs arranged in at least one axial row, wherein theconfronting ends of g a neighboring vane stubs, viewed in the axialdirection, 309O732 5 1963 are spaced from one'another and, in eachinstance, 3l99574 8/l965 et 6 form a gap. Further, the wiper means areoffset in l er 5 l w trailing fashion with respect to the row of vanestubs 3, KG i6! W through an angle less than 900 in the direction ofrota 3 21 L209 10/1965 Latmen et a] "159/6 w tion of the rotor and atleast partially bridge/or overlie g; E fg i x the gap betweenneighboring vane stubs.

a o s on 3,067,812 12/ I962 Latinen et al. I59/6 W 9 Claims, 5 DrawingFigures 14 2/-- F 42 20- 44a ::44b r W m c/b 44 46 52 f" 50 2: so

PATENTEDom m2 3595x327 SHEET 1 OF 2 I INVENT OR Fk/Zz HER BY M/ ATTORNEYPATENTEDHNB I972 SHEET 2 OF 2 INVENTOR [731g [,7 d/ g ATTORNEYBACKGROUND OF THE INVENTION The present invention relates to a new andimproved thin film treatment apparatus for the treatment or handling ofviscous materials.

There are already known to the art different thin film treatmentapparatus having a rotationally symmetrical treatment chamber and arotor arranged in such treatment chamber. Means are provided at therotor of such apparatus which distribute into a thin layer the materialto be treated and introduced into the treatment chamber upon the innerwall of such treatment chamber and sumultaneously impart to suchmaterial a displacement component directed towards the outlet ordischarge connection of the equipment.

According to a known construction of thin film evaporator of this typethe rotor possesses essentially a centrally disposed shaftmember uponwhich there is arranged 'a spiral or helix possessing large pitch.Between the spiral there are mounted upon the shaft member in thedirectionof rotation, and offset through l 80, vane stubs which mutuallyoverlap in the axial direction and whichextend axially. Both the spiralas well as the vane studs extendup to the region of the inner wall ofthe treatment chamber. During operation of this thin film evaporator,the material introduced into the treatment chamber is contacted by thespiral and spread in the form of a thin layer upon the treatment wall.The vane stud following the spiral only performs a smoothingaction uponthe surface of the thin film.

This apparatus possesses the primary disadvantage that as soon'as thetreatment wall is covered with a thin layer of the material to betreated, the surplus material is practically conveyed by the spiral in asingle thrust through the treatment chamber. It should be apparent thatsuch excess material is subjected to a shorter treatment time, andtherefore, experiences a less intensive heart treatment than thatmaterial which has been deposited upon the treatment wall. Hence, thematerial discharging from the treatment chamber does not possess anyuniform properties.

A further considerable drawback of this thin film evaporator resides inthe fact that the throughflow velocity of the material engaged by thespiral is directly proportional to the rotational speed of the rotor.

Since the treatment temperature as well as also the duration oftreatment is relatively fixed for a predetermined material and, as ageneral rule, must be maintained within narrow limits, the speed ofrotation must be coordinated to this predetermined treatment time.Therefore, it is not possible to accommodate the speed of rotation toother factors, which for instance influence the treatment intensity orthe uniformity of the product.

It is known that viscous liquids which exhibit rheological properties,experience a reduction of the viscosity in suitable thin film treatmentapparatuses, which is desirable for different reasons. This phenomenaresults in the presence of shearing stresses which occur upon wiping theviscous liquid between the wall of the treatment chamber and the wipingelement, for instance the vane or wiper element. The magnitude of theseshearing stresses and, therefore, also the reduction of the viscosity,among other things, is also dependent upon the speed of rotation of therotor. Now, if the rotational speed of the rotor is already determinedby virtue of other factors, then utilization of these rheologicalproperties cannot occur in optimum fashion.

SUMMARY OF THE INVENTION ing processing in an efficient, reliable andsatisfactory manner, resulting in a uniform product.

Still another significant object of the present invention relates to animproved thin film treatment apparatus which is relatively simple inconstruction, ex-v tremely reliable in operation, not readily subject tobreakdown, and extremely efficient in carrying out proper treatment of amaterial according to desired processing conditions.

Now, in order to implement these and still further objects of theinvention, which will become more readily apparent as the descriptionproceeds, the inventive thin film treatment apparatus possesses materialconveying means which are formed from a number of vane stubs which arearranged in at least one axial row, wherein the confronting ends ofneighboring vane stubs, viewed in axial direction, are spaced from oneanother and, in each instance, form a respective gap. Furthermore, thewiper means are offset in trailing fashion in the direction of rotationof the rotor with respect to the row of vane studs through an anglewhich is less than and at least partially bridge the gaps betweenneighboring vane stubs.

Due to the fact that the conveying means, instead of being formed as acontinuous spiral, now consist of a plurality of vanes, there isprevented that the material to be treated is conveyed through theapparatus without experiencing any residence time upon the treatmentchamber walls. Quite to the contrary, the conveying, distribution andtreatment of the material occurs stepwise and alternatingly. Thisresults from the fact that the material conveyed by one vane cannotarrive in the operable region of a successive vane in the dischargedirection, before this material has been contacted and treated by thewiper means.

Since the wiper means directly trail or follow the vanes during therotation of the rotor, the wiper means act upon the collected materialwhich forms at the discharge end of each vane, and specifically, beforethis collection of material has flown away under the influence of theforce of gravity. The wiper blade members therefore act extremelyintensively upon the material which has accumulated. Therefore, theadmixing of the material upon the wall of the treatment chamber isintensified and the distribution of this material upon such wall isimproved.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be betterunderstood and objects other than those set forth above, will becomeapparent when consideration is given to the following detaileddescription thereof. Such description makes reference to the annexeddrawings wherein:

FIG. 1 is a schematic illustration in elevational view of a preferredembodiment of inventive thin film treatment apparatus;

FIG. 2 is a cross-sectional view of the thin film treatment apparatusdepicted in FIG. 1, taken substantially along the line II-II thereof;

FIGS. 3-5 inclusive show in enlarged views three further respectiveconstructions of the inventive arrangement of the wiper blade elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now thedrawings, the exemplary embodiment of thin film treatment apparatusdepicted in FIG. 1 will be seen to comprise an essentially verticallyarranged, rotationally symmetrical treatment chamber 12. An inletconnection 14 is provided at the chamber wall 120 at the upper end ofthe treatment chamber 12 and at the lower end thereof, coaxially withrespect to such treatment chamber, there is provided the outlet ordischarge connection 16. This outlet connection 16 is operativelyconnected with the treatment chamber 12 by means of an associatedconical member 18. Continuing, it will be understood that the treatmentchamber 12 is encircled or surrounded by a suitable jacket 20 which isprovided with an inlet connection 22 and an outlet connection 24 for asuitable heating or cooling medium. In similar fashion, the conicalmember 18 is encased by a jacket 26 which is equipped with an inletconnection 28 and an outlet connection 30. Additionally, at the upperend of the treatment chamber 12 there is provided a vapor chamber orcompartment 32 which possesses a diameter corresponding to that of thetreatment chamber 12. The upper end of this vapor compartment 32 isclosed by a cover member 36. Finally, at the wall or jacket 'of thevapor compartment 32 there is provided the vapor discharge connection34.

Now, extending coaxially with respect to the treatment chamber 12 andthe vapor chamber 32 and arranged therein, there is a rotor member 40which essentially extends over the entire length of the treatmentchamber 12 and the therewith connected vapor chamber 32. This rotormember 40 embodies a substantially centrally disposed rotor body memberor shaft 42 which is connected at its upper end with a shaft stub 56and, in turn, is rotatably mounted in a bearing 54 arranged in the covermember 36. The shaft stub 56 is coupled with a suitable drive motor 58.

The end of the central tubular rotor body 42 which confronts or facesthe outlet connection 16 is rotatably mounted at the inner wall 120 ofthe treatment chamber 12 by means of a rim member 50 through the agencyof a number of webs 51 (FIG. 2) which are connected with the tubularbody member 42 of the rotor. At the outer periphery of the rim member50there are provided grooves or ridges 52 which are inclined with respectto the axis of the rotor 40, and the significance of which will be morefully explained hereinafter.

The section of the tubular rotor body member 42 extending over thelength of the treatment chamber 12, will be seen to be equipped with tworadial, axially extending rows of conveyor elements, which are displacedthrough an angle of 180 with respect to one another, and which arecomposed of a plurality of vane stubs 44. More precisely, it will beobserved that the vane stubs 44 are secured to the tubular body member42 by means of the webs or struts 45 (FIG. 2) along an imaginary helicalline. Further, the vane stubs 44 are inclined with respect to the axisof the rotor 40 and in the direction of rotation of the rotor.Furthermore, axially extending wiper elements 46 are secured to thetubular rotor body member 42 between the vane elements 44 arranged inaxial rows. It is important for the functionality of the apparatus thatthe wiper elements 46, in the peripheral or circumferential direction,together with the material conveying element 44, form an angle 0:(alpha) which is smaller than This first material conveyor wiper elementcombination is followed by a second wiper-material conveyor combinationspaced to provide an angle [3 (beta) between the first wiper 46 and thesecond material conveyor 44. Thus, it will be appreciated that the 012/3ratio enables the wiped film to remain in contact with heat exchangesurface of treatment chamber 12 for a longer time. A plurality ofaxially extending wipers 48 are arranged at the region of the vaporcompartment 32 upon the tubular rotor body member 42.

Additionally, it is to be understood that a suitable material removaldevice, in this instance in the form of a removal worm member 60 isprovided in the conical member 18. The material removal worm member 60is rotatably connected via a shaft stub 62 with an appropriate drivemechanism 66. This shaft stub 62 is rotatably mounted in a bearing 64arranged at the discharge or outlet connection 16.

During operation of the heretofore described thin film apparatus 10, theviscous material to be treated is introduced into the treatment chamber12, which is heated and/or cooled by the jacket 20, via the inletconnection 14 and is engaged by the wiper elements 46 and the vane stubs44 which are placed into rotation. Whereas the wiper elements 46 spreadthe engaged material in the form of a thin film upon the inner wall 12aof the treatment chamber 12, the inclined positioned vane stubs 44impart to the engaged material a displacement component which isdirected towards the discharge or outlet connection 16. As soon as thevane stubs 44 contact the material by means of their inlet or leadingedges 44a, they displace such material in front of each such vane stubfor such length of time until the material has reached the discharge ortrailing edge 44b of such vane stub 44 and remains in the form of amaterial bead 74 (FIG. 3) upon the inner wall of the treatment chamber12 at the region of the gaps 43 between neighboring vane stubs 44. Thenext successive or trailing wiper element 46 now contacts the materialbead 74, spreads the material which has been passed through the gapopening upon the inner wall of the treatment chamber 12 and distributesthe material excess of the bead 74 upon the entire width of the wiperelement 46. The next successive vane stub 44 as well as the wiperelement 46 repeat this treatment for such length of time until theviscous material has reached the lower end of the rotor 40. By means ofthe inclined slots or grooves 52 provided at the Supporting ring member50 the tre'ated material is further conveyed into the discharge orremoval worm member 60. This material removal worm member 60, in turn,presses the treated material under large pressure through the outletconnection 16 where it can be further processed, for instance dischargessuch into a suitable container or granulator, which to preserve clarityin illustration has not been shown in the drawmg.

The vapors which are formed during the heat treatment of viscousmaterials ascend in countercurrent with respect to the viscous materialundergoing treatment, into the vapor compartment or chamber 32, wherethey are contacted by the rotating blades or vanes 48 and separated fromany entraineddroplets which may be present in known manner. The thuscleaned vapor current now arrives via the vapor dischargeconnection 34,for instance, into a suitable non-illustrated condenser. f

Due to the inventive arrangement of thewiper element 46 directly behindthe associated vane studs 44, there is achieved a considerablygreate'rutilization of the useful treatment surface incontrast to theknownapparatuses for thetreatment of viscous materials. This is attributableto the fact. that the. material collected into a bead by the vgane stubs44 is again completely distributed by the next successive ortrailingwiper'blades 46 and spread once again in the form of a thin filmupon the inner wall of the treatment chamber 12. In so doing, a portionof the material again comes into-the operable region of the highersituated vane stubs 44, so that for the further conveying of apredetermined quantity of material, on the average alarge number of'wiping contacts of the inner wall of the treatment chamber 12 by thevane stubs 44 is necessary than such was the case with the previouslyknown apparatuses. This furthermore results in the fact that theresidence time of the material to be treated in the treatment chamber ispractically no longer dependent upon the number of revolutions orrotational speed of the rotor, rather is dependent upon how intensivethe wiper elements 46 tend to spread the material to be treated upon theinner wall of the treatment chamber 12. In other words, the better thatthe material is spread the longer becomes the through passage time.

Moreover, it has surprisingly been found that with the use of vane stubs44 which directly thereat trailing wiper elements 46 the rheologicalproperties of viscous materials can be more extensively utilized. Due tothe operation of 'the apparatus independently of the number ofrevolutions of the rotor the rotational speed or number of revolutionsthereof can beincreased in such a way that the thus generated largeshear stresses result in a considerable reduction of the viscosity ofthe material. This could not be predicted since previously the opinionprevailed that when treating viscous materials only such apparatusescould be used which carried out a continuously pronounced conveyingaction upon the material undergoing treatment. Due to thecharacteristics of the inventive thin film treatment apparatus it isfirst possible to successfully treat viscous material, the viscosity ofwhich, under the influence of the described shear stresses, amounts toabout 30,000

poise.

FIG. 3 illustrates a modified version of wiper element. The marginalportion 72 of the therein illustrated wiper element and which confrontsthe inner wall 12a of the treatment chamber 12 is flexed or bent in adirection opposite to the direction of rotation of the rotor. Thisradially extending wiper element 70 encloses together with the bentmarginal portion 72 an angle a between 100 and l70, advantageouslybetween 130 and l50. Due to the flexed marginal portion 72 of the 'wiperelement 70 there is achieved that the material collected in front of thewiper element 70 is subjected to a wedge action, so that this materialis pressed through between the edge of the flexed marginal portion 72and the inner wall 12a of the treatment chamber 12. This form of wiperelement 70 enhances the processing of highly viscous materials withoutthe danger of clogging the treatment chamber 12.

FIG. 4 illustrates a further embodiment of wiper element. Instead of thewiper element 46 of the type shown in FIG. 2, in this arrangement ablade stub is secured to the tubular rotor body member 42. Furthermore,a blade or leaf spring 82 which is bent or flexed opposite the directionof rotation of the rotor 40 is secured to this blade stub 80 by means ofthe attachment wiping element 84. This blade spring 82 wipes inidleness, during rotation of the rotor 40, along the inner wall of thetreatment chamber 12. However, as soon as the material to be treatedarrives at the operable region of the blade spring 82, such blade springis lightly raised by virtue of the wedge action of the material, so thatthe material to be treated is pressed through between the blade spring82 and the inner wall of the treatment chamber 12. By means of thisarrangement there can be spread an especially thin layer of materialupon the inner wall 12a of the treatment chamber 12.

Finally, in FIG. 5 there is shown a further modification of the wiperelement. Here, it will be seen that hinge elements 94 are provided atthe blade stubs secured to the tubular rotor body member 42. These hingeelements 94 hingedly connect a wiper member or element 92 with the bladestub 90. The spacing between the center of the tubular rotor body member42 and the hinge axis of the hinge joint or member 94 is adjustable insuch a way that the gap between the wiper element 92 and the inner wall12a of the treatment chamber 12 can be exactly adjusted. The use of thewiper element 92 has proven particularly advantageous when the materialto be treated at the beginning of the treatment processes a lowviscosity. By virtue of the gap between the wiper element 92 and theinner wall of the treatment chamber 12, which gap can be controlled insize, it is possible to. also contact materials of low viscosity and toeffectively spread such in the form of a thin layer upon the inner wall12a of the treatment chamber 12.

The wiper elements 46 depicted in FIGS. 1 and 2 need not of necessity beconstructed to be continuous throughout the entire length of thetreatment chamber 12. In fact, each such wiper element 46 can also beformed of a plurality of axially extending partial or componentelements, not shown in the drawing. What is important is only that theindividual partial elements which face the discharge or outletconnection 16, protrude at both sides in axial direction past theradially extending edges of the vane stubs 44. if the properties of thematerial to be treated require a particularly long residence time in thethin film treatment apparatus, then, it is even possible to secure theindividual partial elements in an arrangement which is inclined oppositethe direction of rotation of the rotor 40, so that the treated materialis subjected to a displacement component which is directed towards theinlet connection by virtue of the action of the partial elements of thewiper members 46.

Due to the conveying action of the rotator 40 in the inventive thin filmtreatment apparatus, it is possible to operate such in any randomdesired position. Thus, in case the necessity exists, it is possible tohave the treatment chamber 12 assume an inclined or horizontal position.it is even possible to introduce the material at the lower end of avertically extending treatment chamber and to convey such by means ofthe rotor 40 towards the upper end of the treatment chamber 12, where itis removed by an appropriate mechanism out of the chamber 12.

Furthermore, it can be advantageous if the material removal worm member60, instead of being driven by an independent drive member 66, asexplained above, is directly coupled with the rotor member 40. if thisbe the case, then, the rotor drive mechanism 58 must be appropriatelydesigned to possess a greater driving capacity.

it is, of course, also conceivable to use the inventive thin filmtreatment apparatus for carryinglout reaction processes. In suchinstance the materials to be reacted are advantageously admixed prior tointroduction into the treatment chamber 12. When carrying out reactionsunder exothermic conditions, it is furthermore conceivable to use thejacket for cooling the reacting material. in such case, it is necessaryto deliver via the inlet connections 22 or 24, respectively, a medium tothe jacket 20 which possesses a temperature below the reactiontemperature.

While there is shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto but may be otherwise variously embodied and practicedwithin the scope of the following claims. AC- CORDINGLY,

What is claimed is:

1. A wiped thin film treatment apparatus, especially for treatingviscous materials, comprising means defining a rotationally symmetricaltreatment chamber, heating or cooling jacket means encircling saidtreatment chamber, rotor means within said treatment chamber, said rotormeans comprising a rotor shaft, material conveying means and wipermeans, said material conveying means comprising a plurality of vanestubs arranged in at least one row extending in axial direction alongsaid rotor shaft and being supported thereby, each vane stub having aconveying surface inclined with respect to the axis of rotation of saidrotor shaft at an angle of less than 90 with respect to said axis, eachvane stub further having a leading edge and a trailing edge, eachtrailing edge of one vane stub of said row being spaced from the leadingof the succeeding vane stub of said row as viewed in the axial directionto form a respective axial gap between adjacent vane stubs in said row,which is not swept b y any vane stubs in said row, said wiper meanscomprising at least one wiper member extending substantially over thelength of the treatment chamber said wiper member being angularlyretarded in immediate trailing fashion with respect to said row of vanestubs, said vane stubs forming ridged circumferential arcs of thematerial being treated on the chamber inner surface of substantiallyshortened circumferential extent relative to the circumferential extentand width of the continuously wiped film formed by said wiper member,said ridged arcs being sheared and spread upwardly and downwardlysubstantially immediately by said wiper member after being formed,thereby minimizing the gravitational effects on said ridged arcs andincreasing the wiped film residence time with the heatexchange surfacecontacted.

2. A thin film treatment apparatus as defined in claim 1, wherein saidwiper means at least partially bridges said respective axial gap betweenneighboring vane stubs.

3. A thin film treatment apparatus as defined in claim 1, wherein saidrotor means possesses a discharge end, a removal mechanism disposed atsaid discharge end coaxially with respect to said rotor means andadapted to be driven independent of said rotor means.

4. A thin film treatment apparatus as defined in claim 3, furtherincluding drive means for driving said removal mechanism independentlyof said rotor means.

5. A thin film treatment apparatus as defined in claim 1, wherein saidrotor means possesses a discharge end, a ring member rigidly connectedwith said discharge end of said rotor means for mounting said dischargeend of said rotor means upon the inner wall of said treatment chamber. 5

6. A thin film treatment apparatus as defined in claim 1, wherein saidwiper means comprises at least one wiper blade member having a marginalportion which neighbors the inner wall of said treatment chamber and isrearwardly flexed with respect to the direction of rotation of saidrotor means.

7. A thin film treatment apparatus as defined in claim 1, wherein saidwiper means comprises at least one wiper blade member incorporating ablade stub element and a wiper element, said blade stub element beingsecured to said rotor means, and means for pivotally connecting saidwiper element with said blade stub element.

8. A thin film treatment apparatus as defined in claim 1, wherein saidwiper means comprises at least one wiper blade member incorporating ablade stub element and a wiper element, said wiper element being a bladespring member secured to said blade stub element, each such blade springmember having a wiper edge which contacts the inner wall of saidtreatment chamber.

9. A thin film treatment apparatus as defined in claim 1, wherein saidwiper member is constituted by a radially and axially extending linearwiper blade.

1. A wiped thiN film treatment apparatus, especially for treatingviscous materials, comprising means defining a rotationally symmetricaltreatment chamber, heating or cooling jacket means encircling saidtreatment chamber, rotor means within said treatment chamber, said rotormeans comprising a rotor shaft, material conveying means and wipermeans, said material conveying means comprising a plurality of vanestubs arranged in at least one row extending in axial direction alongsaid rotor shaft and being supported thereby, each vane stub having aconveying surface inclined with respect to the axis of rotation of saidrotor shaft at an angle of less than 90* with respect to said axis, eachvane stub further having a leading edge and a trailing edge, eachtrailing edge of one vane stub of said row being spaced from the leadingof the succeeding vane stub of said row as viewed in the axial directionto form a respective axial gap between adjacent vane stubs in said row,which is not swept by any vane stubs in said row, said wiper meanscomprising at least one wiper member extending substantially over thelength of the treatment chamber said wiper member being angularlyretarded in immediate trailing fashion with respect to said row of vanestubs, said vane stubs forming ridged circumferential arcs of thematerial being treated on the chamber inner surface of substantiallyshortened circumferential extent relative to the circumferential extentand width of the continuously wiped film formed by said wiper member,said ridged arcs being sheared and spread upwardly and downwardlysubstantially immediately by said wiper member after being formed,thereby minimizing the gravitational effects on said ridged arcs andincreasing the wiped film residence time with the heat exchange surfacecontacted.
 2. A thin film treatment apparatus as defined in claim 1,wherein said wiper means at least partially bridges said respectiveaxial gap between neighboring vane stubs.
 3. A thin film treatmentapparatus as defined in claim 1, wherein said rotor means possesses adischarge end, a removal mechanism disposed at said discharge endcoaxially with respect to said rotor means and adapted to be drivenindependent of said rotor means.
 4. A thin film treatment apparatus asdefined in claim 3, further including drive means for driving saidremoval mechanism independently of said rotor means.
 5. A thin filmtreatment apparatus as defined in claim 1, wherein said rotor meanspossesses a discharge end, a ring member rigidly connected with saiddischarge end of said rotor means for mounting said discharge end ofsaid rotor means upon the inner wall of said treatment chamber.
 6. Athin film treatment apparatus as defined in claim 1, wherein said wipermeans comprises at least one wiper blade member having a marginalportion which neighbors the inner wall of said treatment chamber and isrearwardly flexed with respect to the direction of rotation of saidrotor means.
 7. A thin film treatment apparatus as defined in claim 1,wherein said wiper means comprises at least one wiper blade memberincorporating a blade stub element and a wiper element, said blade stubelement being secured to said rotor means, and means for pivotallyconnecting said wiper element with said blade stub element.
 8. A thinfilm treatment apparatus as defined in claim 1, wherein said wiper meanscomprises at least one wiper blade member incorporating a blade stubelement and a wiper element, said wiper element being a blade springmember secured to said blade stub element, each such blade spring memberhaving a wiper edge which contacts the inner wall of said treatmentchamber.
 9. A thin film treatment apparatus as defined in claim 1,wherein said wiper member is constituted by a radially and axiallyextending linear wiper blade.